You will need download the content from the old account first to your computer or another cloud storage. Then you can sign into your MyVerizon account online for the new line and upload it there. You could also consider using a different cloud service since the Verizon Cloud is no longer free to use except for contacts.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
The merge accounts is to merge a FiOS cloud with a Wireless cloud and not two wireless clouds. If the old phone number is disconnected and it's been less than 30 days, you can call support at 800-922-0204 and ask them to "unarchive" your old phone number's cloud content into your new phone number's cloud.